Characterization of microsatellites in Xanthosoma sagittifolium (Araceae) and cross-amplification in related species

Xanthosoma sagittifolium (L.) Schott (Araceae) is a monocotyledon aroid native to the tropical Americas, but its original place of domestication is still unknown. It is widely distributed throughout tropical regions in Africa, Southeast Asia, and Oceania. It is an allogamous species cultivated exclusively by vegetative propagation, preventing any possible genetic recombination. Its adaptive capacity is therefore almost nonexistent, and it is vulnerable to various pathogens such as dasheen mosaic virus (DMV ) or Pythium myriotylum Drechsler ( Lebot, 2009 ). Genetic resources are therefore of great value and need to be carefully identifi ed, conserved, and protected. To date, the molecular genetic diversity of this plant has been investigated using only RAPD markers ( Schnell et al., 1999 ; Offei et al., 2004 ) within a limited number of accessions and across restricted areas. The management of ex situ collections and the accurate identifi cation of clones are often hampered by the lack of effi cient markers. Present knowledge on wild crop relatives, population genetics, and spatial distribution of this species is insuffi cient and limited. It is therefore necessary to develop highly polymorphic codominant markers in X. sagittifolium . Microsatellites or simple sequence repeats (SSRs) are highly polymorphic markers that are codominant and widespread in the genome. Such characteristics make them useful for a large range of applications in genetics. Consequently, they have been developed for a large number of plant species. Here, we present the fi rst set of polymorphic nuclear microsatellite markers suitable for germplasm diversity studies and further genetic conservation in X. sagittifolium . Additionally, the microsatellite primers that gave good results were tested for cross-amplifi cation in related Xanthosoma and Caladium species. (Résumé d'auteur)